The Kingston rear large picturewindow gets dirty with the least amount of moisture, I would think some brands with the window set in may not have this problem, but I do not know. Anyway, back to solving the issue, I was thinking that I may be able to install some kind of gutter above the window to divert the water. Has anyone tried this installation?

Sheltyie RV, thanks for the reply, I have looked at this before and someone had mentioned before, that where the back attaches to the roof that their area was high enough to divert the water totheir side gutters. Ours is not and I could add eternabond tape to that area but in time it will release. I was thinking of adding some type of gutter above the window, I'll look at it some more.

BDLuke, Rain-X is something we could try. I know some rv's seem to to be built up a little higher such as Sheltie's, so I was thinking of purchasing a small gutter that I have seem on the net and placing it above the window. It is not that bad, but if we could get rid of the problem I would go for it.